Outline

Objective: There are still many discussions about surgery for Chiari I Malformation (CM) and Syringomyelia in children, both on indications and on surgical technique.

Methods: The present study concerns 80 children operated for CM at the National Neurological Institute of Milan between 1986 and 2007. Age at time of surgery ranged from 1 up to 17 years (mean 11). Preoperative MR was performed in every case and extended on the whole neuraxis to role out associated malformations. All the patients had symptoms before surgery, in the 60%due to the associated syringomyelia; headache and nystagmus prevailed in the pure CM; 4 children presented fluctuating acute paraparesis, before surgery that regressed afterwards. 7 cases had an associated developmental and behavioral disorder with macroencephalia. A small subgroup had an associated craniostenotic pattern.

The surgical treatment was chosen on the basis of the “pathogenetic” subgroup. The “adult” CM were submitted to “classical” decompression with dural patch; in the ”craniostenotic” subtype limited osseous CVD was performed. An arachnoidal opening and tonsillar resection, was reserved for “megaloencephalic” patients and reoperations due to failure of the less invasive procedures.

Results: There were no major surgical morbidity and no mortality. The preoperative symptoms improved more in this pediatric series than in the adult cases treated at our Institution in the same period; an explanation could be the shorter duration of symptoms. In our hands, the results of the limited extradural decompression were poor. In “megaloencephalic” CM an unexpected neuropsychiatric improvement was observed after tonsillar resection. The associated Syringomyelia reduced in more than 80% of children and disappeared in a significant number.

Conclusions: Children may present peculiar picture of CM, like syncope and acute paraparesis. The clinical Symptoms are often more serious than in the adult population, but the results of surgery, especially on the syrinx, are better.